The apparatus and method disclosed in said U.S. Pat. No. 4,365,570 represent a major advance in the boardsailing art. ("Boardsailing", "sailboard", etc., comprehend, as employed in this specification and claims, all types of single-person sailing craft in which (a) the operator stands at all times, and (b) the thus-standing operator steers the craft by tilting the mast in various directions. The sailing may occur on water, on land, or on ice or snow. The "board" or other hull means on which the operator stands may float or may be wheeled, have runners or skis, etc.
There are, however, important problems and goals not solved or achieved by the prior art, which art includes (for example) German Utility Model No. 7421380, issued Dec. 12, 1974. (Such Utility Model shows a form of curved single boom that rotates about a generally horizontal axis.) The important problems include, among others, the following:
(a) Sand, whether it be typical "grit" or "grain" sand or the extremely fine coral sand present on many beaches. Boardsailers often drag portions of sailboard rigs across beaches, which can cause sand infiltration into the bearings. Such infiltration is, frequently, not obviated even after the rig is immersed in the water. PA1 (b) Friction, especially when augmented by sand infiltration. The rotating boom must not seize or bind. Furthermore, and very importantly, the rotation of the boom must not twist or wrap the outer ends of the sail elements about the outer end of the boom. PA1 (c) Outhauling of the sails. The upper and lower sails must have the proper outhauled relationship, relative to each other, in order to achieve the most effective lapped sealing relationship described in U.S. Pat. No. 4,365,570. Furthermore, it is extremely desirable that the operator be able to achieve a precise desired outhaul adjustment of both sails while he is actually sailing along, and even while leaning back in the balanced condition so characteristic of the sailboarding art, because such adjustment increases the efficiency and speed of sailing on various tacks and with variable wind speeds. PA1 (d) Proper boom curvature, so that the boom will not appear awkward to the sailboarder, or even create pain in, or injury to, his wrist while he hangs on the boom hour after hour, and so that the boom may rotate between close-hauled sail components. PA1 (e) High-strength connection of the boom to any desired point on the mast, without requirement for tools, and without interference with boom rotation or boom angle. PA1 (f) Matching of boom length to sail length, to avoid a boom-sail relationship whereby the outer boom end sticks out an excessive distance past the sails. PA1 (g) Good aesthetics, relatively low cost, and simplicity vis-a-vis the boom and its hardware. The achievement of these major goals is crucial, especially where a drastically novel sail rig must compete commercially with long-known booms (and hardware) of non-rotating construction. PA1 (h) Small size. It is a distinct advantage if sails, boom, and hardware (everything except board and mast) can be shipped, stored, and stowed in a relatively small space.
The present invention solves all of the above problems and achieves all of the above goals. Particularly when employed in conjunction with the apparatus and method of said U.S. Pat. No. 4,365,570, there is attained an entire highly-advanced generation of sailboards and rigs therefor.